As used herein, the term “refrigerant unit” or “refrigeration unit” is employed as a generalized term that encompasses equipment broadly used in heating, ventilation, air conditioning and refrigeration (HVACR) systems. The HVACR markets have been served by manual, analog gauge sets for many decades. FIG. 1 depicts a conventional gauge set used for monitoring and collecting system conditions of a refrigerant unit such as pressure, which may then be used to calculate system parameters such as superheat and subcooling. The gauge set permits a service technician to see inside the system to help diagnose and repair faulty systems and components.
As seen in FIG. 1, a conventional gauge set 10 is an analog gauge set that uses a set of hoses 11 connected to a manifold with valves 12. There is a set of analog pressure gauges 14, typically a high side pressure gauge (often identified with a red color) and a low side pressure gauge (often identified with a blue color). The hoses are attached to the system via a flare quick connection (commonly referred to as an SAE connection) for both the low side and high side of the refrigeration unit or air conditioning system. The refrigerant pressure is transmitted via the hoses, through the manifold and up to the analog gauges, and the gauges display the pressure to the technician.
For the service technician to calculate superheat or subcooling, a temperature sensor is attached to the refrigeration unit to measure temperature of the refrigeration. This temperature sensor operates as a temperature meter that is manually attached to the outside of a refrigerant tube near the pressure port where the gauge set hoses are attached. FIGS. 2 and 3 (FIG. 3 being a more close-up view) depict the installation of the conventional gauge set 10 and temperature sensors 16 within an air conditioning unit 18. The temperature and pressure are then used by the technician to manually calculate superheat and subcooling. In particular, as is known in the art, there are established calculations by which superheat and subcooling are calculated based on the measured temperature and pressure parameters.
The conventional hose gauge system has significant deficiencies. The refrigerant travels through the length of the hoses to the analog or digital gauges at the manifold to display pressure. The refrigerant can be in the form of vapor or liquid, with common hose sizes being 5′ or 6′ in length. Under current environmental regulations, refrigerant in the hoses must be collected and reclaimed, and not just released into the environment. A quick connect coupling is available on the market to eliminate refrigerant “blow off” (emptying the refrigeration hoses after system inspection). The coupling is attached to the end of the hoses and essentially traps the refrigerant in the hoses after removing them from the system. The disadvantage of using this form of coupling is that the analog gauge set can only be used for one type of system, i.e., the system refrigerant must be the same type as the trapped refrigerant inside of the hoses or refrigerant and oil contamination will occur.
Relatedly, cross contamination between refrigerant systems must be avoided. Common practice today is that a service technician needs to have several analog gauge sets for particular refrigerants. For example, a technician may have a first gauge set for R-134a, a second gauge set for R-410, and a third gauge set for R-404a refrigerants. By having multiple analog gauge sets, a technician must be careful to avoid cross contamination among the gauge sets. Cross contamination can cause damage to the gauge set hoses and also reduce system performance, particularly on small systems due to incompatibilities among different refrigerant and oils.
The hoses also are bulky and therefore must be carried and transported. The efforts and inconvenience of transport are increased by the need for multiple gauge sets. Weight and flexibility further are significant for service technicians due to the fact that they are often climbing on ladders and carrying tools to roofs to service roof-top condensing units for refrigeration or air conditioners. Conventional analog gauge sets also require the technician to stand next to the gauge set to read pressure, or two technicians with two-way radios or equivalent mobile devices may need to report measurements to each other. The close distance requirements of conventional analog gauge sets provides yet another deficiency of such systems.